Fixes

• Fix crash where a synchronous effect render unmounts the tree (#5026, thanks @JoviDeCroock)

Performance

• Core size optimizations (#5022, thanks @JoviDeCroock)
• Hooks size optimizations (#5021, thanks @JoviDeCroock)
• Make oldProps diffing more compact (#5004) (#5019, thanks @JoviDeCroock)
• Compat size optimizations (#5020, thanks @JoviDeCroock)
• Land size optimization separately (#5018, thanks @JoviDeCroock)

Fixes

• Forward-port fixes from v10 (#5008, thanks @JoviDeCroock)
• Avoid scheduling suspense state udpates (#5006, thanks @JoviDeCroock)
• Resolve some suspense crashes (#4999, thanks @JoviDeCroock)
• Support inheriting namespace through portals (#4993) (#4995, thanks @JoviDeCroock)
• Forward-port diffing fix (#4976, thanks @JoviDeCroock)
• Fix cascading renders with signals (#4966) (#4969, thanks @JoviDeCroock)
• Avoid lazy components without result going in throw loop (#4939, thanks @JoviDeCroock)
• Support XHTML phrasing content in MathML token elements (#4924, thanks @rschristian)
• Check excess for preact-iso (#4898, thanks @JoviDeCroock)

Types

• Export setupComponentStack (#4974, thanks @ssssota)
• Add types for 'getDisplayName' (#4957, thanks @rschristian)
• Adds scrollsnapchange and scrollsnapchanging event support (#4946, thanks @argyleink)
• Fix scroll events (#4948, thanks @rschristian)
• Updates dangerouslySetInnerHTML type so future TS will accept Trusted… (#4930, thanks @lukewarlow)

Performance

• Call toLowerCase on name regardless of its current casing (#5003, thanks @ali-garajian)
• Set oldProps's default value on declaration (#4959, thanks @ali-garajian)
• Prevent frequently updated components from retaining memory (#4907, thanks @JoviDeCroock)
• Golf down hooks impl (#4897, thanks @JoviDeCroock)
• Save bytes by inlining ref unmount checks (#4896, thanks @JoviDeCroock)
• Save bytes on hydration 2.0 (#4894, thanks @JoviDeCroock)

Maintenance

• Remove leftover codemods (#5000, thanks @rschristian)
• Clean configs (#4996, thanks @rschristian)
• Force strict equality on vnode constructor (#4986, thanks @JoviDeCroock)
• types: Correct outdated imports in jsx-runtime (#4981, thanks @rschristian)
• Delete redundant code of conduct (#4962, thanks @JoviDeCroock)
• Update CODE_OF_CONDUCT to include LLM usage guidelines (#4961, thanks @JoviDeCroock)
• Add comments for hooks options (#4942, thanks @situ2001)
• Add commpat/server.browser entry (#4940, thanks @marvinhagemeister)
• Switch tests to use .jsx file extension (#4925, thanks @rschristian)
• Fix PR reporter for non-main branch targets (#4900, thanks @rschristian)

Fixes

• Avoid scheduling suspense state udpates (#5006, thanks @JoviDeCroock)
• Resolve some suspense crashes (#4999, thanks @JoviDeCroock)
• Support inheriting namespace through portals (#4993, thanks @JoviDeCroock)

Maintenance

• Update test with addition of _original (#4989, thanks @JoviDeCroock)

Fixes

• Enforce strict equality for VNode object constructors

Fixes

• Enforce strict equality for VNode object constructors

Fixes

• Enforce strict equality for VNode object constructors

Fixes

• Fix erroneous diffing w/ growing list (#4975, thanks @JoviDeCroock)

Types

• Updates dangerouslySetInnerHTML type so future TS will accept Trusted… (#4931, thanks @lukewarlow)
• Adds snap events (#4947, thanks @argyleink)
• Remove missed jsx duplicates (#4950, thanks @rschristian)
• Fix scroll events (#4949, thanks @rschristian)

Fixes

• Fix cascading renders with signals (#4966, thanks @JoviDeCroock)
• add commpat/server.browser entry (#4941 & #4940, thanks @marvinhagemeister)
• Avoid lazy components without result going in throw loop (#4937, thanks @JoviDeCroock)

Performance

• Backport some v11 optimizations (#4967, thanks @JoviDeCroock)

Types

• Mirror non-JSX types to the 'preact' namespace (#4904, thanks @rschristian)

Fixes

• Address memory leak (#4906, thanks @JoviDeCroock)

Breaking Changes

• Drop IE11 support (#4549, thanks @JoviDeCroock)
• Move defaultProps into preact/compat (#4657, thanks @JoviDeCroock)
• Remove automatic px suffix (#4665, thanks @JoviDeCroock)
• Remove contains with a simple parentNode check (#4666, thanks @JoviDeCroock)
• Remove component.base (#4549, thanks @JoviDeCroock)
• Remove SuspenseList (#4668, thanks @JoviDeCroock)
• Remove static dom bail (#4670, thanks @JoviDeCroock)
• Breaking changes to outputs & pkg.json (#4652, thanks @rschristian)
• Drop support for TS versions < 5.1 (#4788, thanks @rschristian)
• Remove all export maps in nested pkg.json files (#4784, thanks @rschristian)
• Remove deprecated 'ForwardFn' type from compat (#4777, thanks @rschristian)

Features

• Comment denoted hydration (#4636, thanks @JoviDeCroock)
• Forward ref by default (#4658, thanks @JoviDeCroock)
• Add captureOwnerStack (#4875, thanks @colinaaa)
• Add context argument to compat/Children map api (#3855, thanks @ParSal123)
• Export helper functions from preact/debug (#4830, thanks @colinaaa)
• Export test-utils from compat (#4783, thanks @rawrmonstar)

Types

• Require initial value in useRef (#4683, thanks @rschristian)
• Types w/ module augmentation (#4884, thanks @rschristian)
• Fix outdated public RefCallback type (#4801, thanks @developit)
• Export IntrinsicHTMLElements interface (#4885, thanks @edoardocavazza)
• Avoid breaking change for ARIA element types (#4882, thanks @rschristian)
• Move most interfaces out of the JSX namespace (#4878, thanks @rschristian)
• Make HTMLAttribute type declarations consistent (#4876, thanks @rschristian)
• Restrict aria roles by element type (#4607, thanks @rschristian)
• Add types for '/compat/server' & '/compat/scheduler' (#4835, thanks @rschristian)

Fixes

• Ensure memoized components re-render after errors (#4880, thanks @JoviDeCroock)
• Provide solution to long standing memleak (#4853, thanks @JoviDeCroock)
• Ensure we properly re-render bailing errored children (#4857, thanks @JoviDeCroock)
• Support alternative contentDocument (#4851, thanks @JoviDeCroock)
• Fix memory leak in VNode owner tracking (#4850, thanks @developit)
• Ensure 'compat/test-utils' exports match & are valid (#4834, thanks @rschristian)
• Fix signal attribute values not working with precompile transform (#4799, thanks @marvinhagemeister)
• Fix escape style object value in precompile transform (#4794, thanks @marvinhagemeister)
• Fix _listeners mangle to reduce collisions (#4463, thanks @rschristian)

Performance

• Do not re-insert memoized vnodes that keep their relative order after swap (#4888, thanks @vasylenkoval)
• Call tolowercase only when needed (#4881, thanks @JoviDeCroock)
• Reduce some repeated logic (#4814, thanks @43081j)
• Golf down suspense (#4855, thanks @JoviDeCroock)
• Add flags for component type (#4867, thanks @JoviDeCroock)

Refactors

• DOM event name casing (#4843, thanks @rschristian)
• Improve accuracy of non-dimensional regex (#4772, thanks @rschristian)
• Skip dom check for inferring lower-cased event names (#4720, thanks @rschristian)
• Prune portal logic (#4667, thanks @JoviDeCroock)
• Switch to Object.is for hook args (#4663, thanks @rschristian)
• Remove rerendercount (#4877, thanks @JoviDeCroock)

Testing & Development

• Bump testing/transpilation/formatting deps (#4858, thanks @JoviDeCroock)
• Upgrade oxlint to 1.8.0, fix errors (#4848, thanks @camc314)
• Add simple test for unstable_batchedUpdate to improve coverage (#4842, thanks @rschristian)
• Correct PR reporter filter for forks (#4828, thanks @rschristian)
• Remove sinon (#4820, thanks @43081j)
• Migrate compat tests to vitest spies (#4819, thanks @43081j)
• Migrate debug tests to vitest spies (#4817, thanks @43081j)
• Migrate hooks tests to vitest spies (#4816, thanks @43081j)
• Migrate lifecycle tests to use vitest spies (#4815, thanks @43081j)
• Migrate events/refs tests to vitest spies (#4813, thanks @43081j)
• Migrate more browser tests to use vitest spies (#4812, thanks @43081j)
• Migrate context tests to vitest spies (#4810, thanks @43081j)
• Migrate createContext test to use vitest spies (#4811, thanks @43081j)
• Migrate components tests to vitest spies (#4809, thanks @43081j)
• Use v8 coverage (#4807, thanks @43081j)
• Switch to playwright for browser tests (#4808, thanks @43081j)
• Migrate from mocha to vitest (#4806, thanks @43081j)
• Add test ensuring effects are cleaned up (#4792, thanks @JoviDeCroock)
• Avoid caching so file-saves work first try (#4786, thanks @JoviDeCroock)
• Bump browserslist (#4785, thanks @rschristian)
• Specify target browsers (#4773, thanks @rschristian)
• Remove extraneous pkg.json key (#4789, thanks @rschristian)
• Drop unused/broken test (#4653, thanks @rschristian)